There is not one of us who has not entered the door of the Secret Mantra Vehicle. And once we have done so, if we do not subsequently keep the commitments, we will go to hell; if we do keep them, we will attain Buddhahood. There is no other destination than these two.

The Secret Mantra Vehicle commitments are very subtle, numerous, and difficult to keep. Even Lord Atisha said that after he had entered the Mantra Vehicle, he committed fault after fault in rapid succession.

So for us who have few antidotes, weak mindfulness, and no vigilance (we do not even know the different categories of vows, nor the point at which we break the precepts), there can be no doubt that breaches of our vows are falling on us like rain.

We should therefore do the practice of Vajrasattva every day and recite the hundred syllables twenty-one times. By doing so, our downfalls will be blessed and their fully ripened effect will be prevented from growing greater. And by reciting the hundred-syllable mantra one hundred thousand times, all our downfalls will be eradicated, as the Ornament of the Essence says:

Clearly visualize Vajrasattva
Enthroned on a white lotus and moon:
By reciting twenty-one times
The hundred syllables according to the ritual,
Downfalls and the like will be blessed
And therefore not grow greater.

Thus the greatest accomplished beings have taught,
So do this practice constantly.
If you recite it one hundred thousand times,
You will become the very embodiment of total purity.

Even if, for your own part, you have managed — through your stability in the generation and perfection phases, your mindfulness and vigilance, and so forth — to keep faultless commitments, there are others who may have broken the root commitments, and by mixing with them in conversation, joining with them in the same activities, and even drinking the water from the same valley as they, you will get the faults of transgression by association and of incidental transgression. As the tantra says,

I have kept the company of transgressors, fulfilled their wishes,
Given teachings to them and to those unsuitable.
I have thought nothing of those who’ve broken the commitments
And have in turn been tainted by their defilements and faults.

It is also said:

Like one drop of sour milk
That turns all the milk sour,
One degenerate practitioner
Spoils all the other practitioners.

Breaches of Mantra-Vehicle commitments are easy to purify if we part from them properly. The teachings say that if a single root downfall of the vows of individual liberation occurs and is concealed, it is impossible to repair, like a shattered earthen pot. Root downfalls of the Bodhisattva vow are like broken objects made of a precious metal: they can be repaired with the help of someone else, namely a spiritual friend.

Faults and downfalls in the Secret Mantra Vehicle are like slight dents in a precious metal object: one can completely purify them oneself, using the deity, mantra, and concentration as supports. As long as one parts from them immediately, they are easy to purify, but the longer one waits, the more the fault grows, and the harder it becomes to part from it. After three years, they cannot be purified, even if one attempts to part from them.

Dudjom Rinpoche –
A Torch Lighting the Way to Freedom